# Mike’s Blog

> Networking, Linux & security — hands-on from the lab. Written by a working network engineer: hands-on Cisco, Juniper, Cisco ISE, home lab and certification notes. Every post is first-hand — configs and CLI output are from real kit.

Author: Mike (Cisco Champion 2021-24, CCNP Security). Contact: m@ydn.au
Licence: content is the author's own; quote with attribution and a link.

## CISCO

- [Cisco Switch Configuration Best Practices: Build Template](https://mike.ydn.au/cisco-switch-build-template/): A production-grade Cisco switch build template for 2026: type 9 secrets, 4096-bit SSH keys, TACACS+ with a console break-glass, and the full config to copy.
- [Cisco ISE in Azure: When Azure Drops Out-of-Order UDP](https://mike.ydn.au/cisco-ise-azure-deployment/): 802.1X broke on a working Cisco ISE deployment in Azure because Azure drops out-of-order UDP fragments. Root cause, the gateway fix, and a pre-deploy checklist.
- [Cisco ISE First Deployment: What the Docs Won’t Tell You](https://mike.ydn.au/cisco-ise-first-deployment/): Deploying Cisco ISE for the first time: version choice, VM sizing that survives load, licensing tiers, certificate traps, and an order of operations that works.
- [Cisco Config Archive & Rollback: revert vs reload](https://mike.ydn.au/cisco-config-revert-command/): Cisco's configuration archive and the revert timer let you roll back a bad change without a reload — how archive works, and why revert beats reload at 2am.
- [Easily Find Unused Ports on a Cisco Switch](https://mike.ydn.au/easily-find-unused-ports-on-a-cisco-switch/): One Cisco command finds every unused switch port: show int | i proto|Last in. How to read the output, classify ports by activity, and why it's a security check.
- [Site-to-Site IPSec: Juniper to Cisco Through MikroTik NAT](https://mike.ydn.au/site-to-site-ipsec-between-juniper-and-cisco-through-mikrotiks-nat/): IPSec from a Cisco ISR to a Juniper SRX behind a MikroTik LTE router: route-based VTI and st0, NAT-T on UDP 500 and 4500, MSS clamping, and modern crypto.
- [Cisco Native VLAN: How It Works and Why Mismatches Bite](https://mike.ydn.au/cisco-native-vlan-mystery-revealed/): How the 802.1Q native VLAN really works, what a mismatch does to your traffic, and why double tagging is the reason to prune it from every trunk.
- [Cisco Switchport Modes, DTP, and switchport nonegotiate Explained](https://mike.ydn.au/switchport-configurations-explained/): Cisco switchport modes, the DTP negotiation matrix, and why two dynamic auto ports never form a trunk — plus the config that keeps DTP off access ports.
- [DHCP Option 121 and 249: Pushing Routes Clients Actually Install](https://mike.ydn.au/routes-by-dhcp/): How DHCP option 121 and Microsoft's option 249 encode static routes, why the obvious Cisco IOS syntax puts garbage on the wire, and how to build the hex.

## Security

- [Post-Quantum Cryptography and Australia’s 2030 Deadline: What It Means for Your Network](https://mike.ydn.au/post-quantum-cryptography-network-devices/): ASD gives Australia until 2030 to retire RSA, DH, ECDH and ECDSA, five years ahead of NIST. What PQC is, and what your routers and SSH support today.
- [How to make a private VPN server in 10 minutes](https://mike.ydn.au/how-to-make-a-private-vpn-server-in-10-minutes/): Standing up your own WireGuard VPN on a $5 VPS in about ten minutes — the install script, the trade-offs, and what self-hosting does and doesn't protect.

## Home Lab

- [Telnet on macOS for EVE-NG: What Actually Works](https://mike.ydn.au/enable-telnet-on-macos-high-sierra-for-eve-ng/): macOS dropped telnet in High Sierra. Why the disable-SIP fix cannot work now, how to install telnet with Homebrew, and how to fix EVE-NG console links.
- [Making home FreeBSD torrent+NAS server](https://mike.ydn.au/making-home-freebsd-torrentnas-server/): A 2017 FreeBSD 11 Samba and Transmission build kept as written, with the security fixes and packaging changes needed to run it on a supported release.
- [Making Home Lab. Part 1](https://mike.ydn.au/making-home-lab-part-1/): Part 1 of building a home network lab: choosing used Cisco gear, rack and power planning, and the EVE-NG setup that ties the virtual and physical kit together.

## Juniper

- [Juniper SRX Cheat Sheet](https://mike.ydn.au/juniper-srx-cheat-sheet/): The Junos commands worth knowing on SRX gear: the three CLI modes, commit confirmed and rollback, structural config editing, VLANs, zones and policies.

## O365

- [Add Calendar Permissions in Microsoft 365 via PowerShell](https://mike.ydn.au/add-calendar-permissions-in-office-365-via-powershell/): Exchange Online calendar permissions from PowerShell: the V3 connection that replaced New-PSSession, Add- vs Set-, localised folder names, and delegate flags.

## NBN

- [NBN FTTP Connection Box Status Lights](https://mike.ydn.au/nbn-fttp-connection-box-status-lights/): What each light on the nbn FTTP connection box means, read as a fault tree — how to tell in seconds whether a problem is the carrier's or yours.

## Pages

- [About Me](https://mike.ydn.au/about-me/)
- [Site History](https://mike.ydn.au/site-history/)